The relief valve would only leak for one of three reasons. Excessive pressure, excessive temperature, or failure due to age. The rating only determines if the system is going to blow up if the burner does not function properly. Other than age, the valve should have stopped leaking when the temperture or pressure was reduced, so the logical thing is that the house pressure is, or was, too high. One other thing, if the burner were in a run away situation, then the reduced capacity would have allowed the temperature to stay high and thus the water would have kept running. If you had this last situation, I would have advised your wife to go about a block away from the house and then call you. In the worst situation, the house could have met her there.

: Last week the wife called to tell me the water heater was leaking all over the place. Turned out to be the : pressure relief valve had opened on ?. I had a standard t p valve on it, but this is not a tank type heater.: It is an on demand or instantaneous water heater. The old valve was rated at a maximum of 100,000 btuh,: but the new valve is rated at a maximum of 185,000 btuh. The heater is a big one, rated at 165,000 btuh.: Could this have been the problem (wrong valve) or should I continue to investigate. The heater and old : valve are only about 10 months old and seemed to have worked fine. Why would a maximum btu rating: affect this and not the temp or pressure.: Thanks,: Jim Atkinson